I run one with mine but feed it through a mixer to bring up the gain and tailor the audio before the radio. Sounds excellent. The mixer is from eBay and cost me around 30 bucks.
I run my PR781 into a dbx 286s and then to my 7610 and I love it. Very similar to the W2IHY EQPlus at about half the price. I run out of the 286s and then into a W2IHY Iplus so I can direct my mic audio, paddle, and PTT to three different radios. Works great. 73
The IC-7300 and Icom again returned to the low power preamp we see in the older Icom radius. The PR-781 is simply not appropriate for this radio. The Heil ICM is what you need, it is an electret mic, and it works very well with the 7300. On the other hand, the IC-7800 works very well with a PR-781 right out of the box.
You/ Bob Heil/ and I agree on that. Sure you can make it work by turning the gain up but that's not the appropriate way to do run it and your ALC may not work properly. You'll get better audio out of the Heil IC type mic running much lower settings. Running an intermittent preamp mixer will work
For the 7800 you will want to go with the PR 781 Mic gain about 1/3 up to 1/3 comp + 3 or 4 on highs and - 1 on low to start, it will work great
The PR-781 is obviously a great mic. That said, I'm a PR-40 guy. It is fantastic. Great forward gain, great side and rear rejection, and most importantly of all, great audio. Hard to beat, in my opinion.
Sure glad that 40 years ago I bought a Shure 444 and have never had to bother about microphones ever since! 73 de Mike VK3KTO
I never understood why someone would spend $180 on a mike, or even over $400 for a PR-40, to be used on a communication channel that is 2700 Hz wide and "infested" with interference, phasing and whatnot. And don't give me the "it's tailored to the human voice" argument because that can be achieved with the EQ present in any modern rig or with a small outboard mixer with a parametric EQ. Is it really beneficial to have such an expensive mike or is it just "wow, I like the look of me behind that mike"? Ok, I braced myself, go and hit me!